ABSTRACT New U-Pb geochronology and a large and growing geochemical data base has clarified the age and composition of the extensive magmatic belts of NE Russia, allowing a better understanding of their relation to the plate tectonic evolution of the circum- Pacific margins of Russia, Alaska and the North American Cordillera, as well as to plate tectonic events that formed the Arctic Ocean. Prior to the magmatism described here, the paleo-Pacific margin of Siberia (now the Verkhoyansk-Kolyma orogen), Arctic Chukotka and the Brooks Range, Alaska, shared passive margin sedimentation from the Triassic to mid-Jurassic. Deformation along this once contiguous margin began with closure of deep-water basins and culminated with emplacement of oceanic and arc rocks onto the margin with continuing shortening of the margin into the Jura-Cretaceous. The Main Kolyma batholith belt (calc-alkaline granites to granodiorites) (158-144 Ma, peak 150±3 Ma) and the paired Uyandina-Yasachnaya volcanic arc are thought to have resulted from west-dipping subduction. Northern belt plutons (calc-alkaline) are 140-129 Ma and mostly post-date the E-W trending oroclinal bend of the northernVerkhoyansk fold belt. Calc-alkaline granites to granodiorites spanning 125-100 Ma intruded across Chukotka (Artic Russia) and Alaska during extension, right lateral shear and subduction zone retreat towards the Pacific perhaps coeval with the onset of rifting in the Amerasia Basin of the Arctic. The Uda-Murgal arc evolved independently along the Taigonos and Okhotsk part of the Russian margin, between 150-130 Ma and 107-97 Ma, and was followed by the establishment of the margin-parallel Okhotsk-Chukotka volcanic belt (OCVB), erupted in a neutral to slightly extensional tectonic regime, beginning 106 Ma, but, mostly between 98-80 Ma and ending ~ 76 Ma. Age equivalent magmatism in the Bering Strait is associated with continued extension, melting and remobilization of the deep crust. Between 80-60 Ma, subduction-related magmatism stepped south to the outer Bering Shelf and then to the Aleutians before 46 Ma. A similar process occurred in Russia with the pre-55 Ma onset of opening of the Sea of Okhotsk and step-wise migration of the subduction zone to eastern Kamchatka and Kuril Islands. These events broadly coincide with the opening of the Eurasia Basin of the Arctic. Profound differences occur in the tectonic setting of magmatism through time along strike of the subducting margin from Russia to the North American Cordillera. From 125 to 60 Ma, the NE Russian and Alaskan sectors of the margin underwent mostly neutral to extensional tectonism while the Cordillera underwent crustal shortening. Although vast amounts of paleo-Pacific oceanic lithosphere were subducted beneath both sectors of the margin, it appears that in a mantle reference frame, the Cordillera moved mostly towards its subduction zone while the overriding continental plates in NE Russia and Alaska moved parallel to or away from their subduction zones, allowing magmatism to take place in tectonically neutral or extensional settings. The coupled timing of trench-towards versus trench-away events related to motion of the overriding plates led to the observed “dance” of magmatism and deformation along the northern circum-Pacific margin.

中文翻译：

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沿北环太平洋边缘的晚中生代岩浆活动和变形的发作性和舞蹈：nerussia 到山脉

摘要 新的 U-Pb 年代学和不断增长的大型地球化学数据库澄清了俄罗斯东北部广泛岩浆带的年龄和组成，从而更好地了解它们与俄罗斯环太平洋边缘板块构造演化的关系，阿拉斯加和北美山脉，以及形成北冰洋的板块构造事件。在这里描述的岩浆作用之前，西伯利亚的古太平洋边缘（现在的 Verkhoyansk-Kolyma 造山带）、北极楚科奇和阿拉斯加的布鲁克斯山脉共享从三叠纪到中侏罗纪的被动边缘沉积。沿着这个曾经连续的边缘的变形开始于深水盆地的关闭，并随着大洋和弧形岩石在边缘上的侵位而达到顶点，边缘继续缩短到侏罗纪白垩纪。科雷马主基岩带（钙碱性花岗岩到花岗闪长岩）（158-144 Ma，峰值 150±3 Ma）和成对的 Uyandina-Yasachnaya 火山弧被认为是西倾俯冲的结果。北部带岩体（钙碱性）为 140-129 Ma，大部分时间晚于北 Verkhoyansk 褶皱带的 EW 向斜弯。钙碱性花岗岩到花岗闪长岩跨越 125-100 Ma，在伸展过程中侵入楚科奇（北极俄罗斯）和阿拉斯加，右横向剪切和俯冲带向太平洋撤退，可能与北极亚美西亚盆地裂谷的开始同时期。Uda-Murgal 弧沿着俄罗斯边缘的 Taigonos 和鄂霍次克部分独立演化，在 150-130 Ma 和 107-97 Ma 之间，随后是与边缘平行的鄂霍次克-楚科奇火山带（OCVB）的建立，在中性到轻微伸展的构造体制中喷发，从 106 Ma 开始，但主要在 98-80 Ma 之间，结束于 76 Ma。白令海峡的同龄岩浆活动与深部地壳的持续伸展、熔化和再活动有关。在 80-60 Ma 之间，与俯冲有关的岩浆活动向南延伸到外白令陆架，然后在 46 Ma 之前到达阿留申群岛。随着鄂霍次克海的开放和俯冲带逐步迁移到堪察加东部和千岛群岛，俄罗斯也发生了类似的过程。这些事件与北极欧亚盆地的开放大致相符。随着时间的推移，从俄罗斯到北美科迪勒拉的俯冲边缘走向，岩浆活动的构造环境发生了深刻的差异。从 125 到 60 Ma，边缘的俄罗斯东北部和阿拉斯加部分经历了大部分中性到伸展构造作用，而科迪勒拉则经历了地壳缩短。尽管大量古太平洋海洋岩石圈被俯冲到边缘的两个部分之下，但在地幔参考系中，科迪勒拉山脉似乎主要向其俯冲带移动，而俄罗斯东北部和阿拉斯加的上覆大陆板块则平行或远离从它们的俯冲带，使岩浆活动发生在构造中性或伸展的环境中。